A server, one of data processing apparatus, has redundantly configured memories in some cases. Even if an error occurs on one of the redundantly configured memories, the server may thereby continue a process by using another regularly working memory. Some server accesses a memory by using an interleave function so as to achieve higher speed access to the memory. That is, the server divides data of consecutive addresses when the data is written into the memory, and puts a portion of the divided data on an interleave block of every way, i.e., one of areas into which the memory is divided. When the server reads data having been written, the server reads a plurality of portions of the data of the consecutive addresses put on the interleave blocks of the respective ways in parallel so as to achieve higher speed access to the memory. In such a case, a type of interleaving in case of dividing a memory into two interleave blocks is called 2-Way interleaving, and a type of interleaving in case of dividing a memory into four interleave blocks is called 4-Way interleaving.
In a case, however, where a server stores data in a memory on the basis of, e.g., a 2-Way interleave setting and then changes the 2-Way interleave setting to, e.g., a 4-Way interleave setting, an address that data is written into and an address that data is read from disagree with each other. Such disagreement results in that the data written into the memory and the data read from the memory do not match each other. Thus, if the server needs a change in an interleave setting because of, e.g., addition of a memory, the interleave setting is changed after the server stops working and after a process for rebooting the server.